Car operated safety gate for horizontally transferrable elevator cab

ABSTRACT

A safety gate (24) is slidable vertically from an upper position at an elevator cab landing (22) where it obstructs movement of the elevator cab (20) into a hoistway, and a lower position that permits cab travel between a car frame (29) and the landing. An actuator (42) normally urges the gate upwardly; the actuator is moved by a cam assembly (36) on an approaching elevator car frame so as to slide the gate (24) downward, out of the way of cab motion.

TECHNICAL FIELD

This invention relates to a safety gate that prevents a horizontallymoveable elevator cab from entering an empty hoistway, the gate beingmoved out of the way by an approaching elevator car frame to permittransfer of a cab between the landing and the car frame.

BACKGROUND ART

The sheer weight of the rope in the hoisting system of a conventionalelevator limits their practical length of travel. To reach portions oftall buildings which exceed that limitation, it has been common todeliver passengers to sky lobbies, where the passengers walk on foot toother elevators which will take them higher in the building. However,the milling around of passengers is typically disorderly, and disruptsthe steady flow of passengers upwardly or downwardly in the building.

All of the passengers for upper floors of a building must travelupwardly through the lower floors of the building. Therefore, asbuildings become higher, more and more passengers must travel throughthe lower floors, requiring that more and more of the building bedevoted to elevator hoistways (referred to as the "core" herein).Reduction of the amount of core required to move adequate passengers tothe upper reaches of a building requires increases in the effectiveusage of each elevator hoistway. For instance, the known double deck cardoubled the number of passengers which could be moved during peaktraffic, thereby reducing the number of required hoistways by nearlyhalf. Suggestions for having multiple cabs moving in hoistways haveincluded double slung systems in which a higher cab moves twice thedistance of a lower cab due to a roping ratio, and elevators powered bylinear induction motors (LIMs) on the sidewalls of the hoistways,thereby eliminating the need for roping. However, the double slungsystems are useless for shuttling passengers to sky lobbies in very tallbuildings, and the LIMs are not yet practical, principally because,without a counterweight, motor components and power consumption areprohibitively large.

Since the loading and unloading of passengers takes considerable time,in contrast with high speed express runs of elevators, another way toincrease hoistway utilization, thereby decreasing core requirements,includes moving the elevator cab out of the hoistway for unloading andloading, as is described in a commonly owned, copending U.S. patentapplication Ser. No. (Attorney Docket No. OT-2297), filedcontemporaneously herewith.

DISCLOSURE OF INVENTION

Objects of the invention include provision of a mechanical safety deviceto ensure that horizontally moveable elevator cabs do not enter ahoistway except when there is an elevator car frame adjacent to thelanding.

According to the present invention, a vertically slidable gate memberextends above a landing to prevent a horizontally moveable elevator cabfrom entering an adjacent hoistway, and the gate is lowered by anactuator operated by an approaching elevator car frame. Accordingfurther to the invention, the safety gate may be lowered in response toan upward-traveling car frame or in response to a downward traveling carframe.

Other objects, features and advantages of the present invention willbecome more apparent in the light of the following detailed descriptionof exemplary embodiments thereof, as illustrated in the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a stylized, partially sectioned, broken away side elevationview of a safety gate according to the invention at the top of ahoistway when lowered by the presence of an elevator car.

FIG. 2 is a partial, partially sectioned and broken away perspectiveview of the safety gate of FIG. 1.

FIG. 3 is a stylized, partially sectioned, broken away side elevationview of the safety gate of FIG. 1 when latched in an upper, operativeposition, as an upwardly traveling elevator car approaches it.

FIG. 4 is a stylized, partially sectioned, broken away side elevationview of the safety gate of FIG. 1 as a safety catch is released by a camon an approaching elevator car.

FIG. 5 is a stylized, partially sectioned, broken away side elevationview of an alternative form of the invention at the bottom of a hoistwayoperable by a downwardly-traveling elevator car, when latched in theupper operative position, as an elevator car approaches it.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to FIG. 1, an elevator cab 20 is disposed on rollers 21 sothat it may be rolled across the surface of a transfer floor 22 in abuilding over a slot 23 in the floor within which is slidably disposedthe safety gate 24 of the present invention. When hoistway doors 27 areopen, the cab 20 may roll onto an elevator car frame 29 with its rollers21 within tracks 30. A mounting plate 31 is disposed on a frame member32 that is attached to the plank of the car frame (not shown), and whichalso supports an angle brace 33 of the well-known type. The mountingplate 31 supports a cam structure 35 which includes an angled camsurface 36, a vertical cam surface 37, and a roller 38 rotatablydisposed on an arm 39.

An operating arm 42 extends through a slot 43 in the gate 24 and isrotatably fastened to the hoistway wall 44 (FIG. 2) by a pivot 45. Thepivot 45 may be secured to a mounting plate 46 that can be secured in asuitable fashion to the wall 44 or a hoistway frame, such as with bolts47. In FIGS. 2 and 3, the gate 24 is shown in an upper, operativeposition with the arm 42 latched in its fully counterclockwise positionby means of a catch 51. The catch 51 is rotatably disposed on the plate46 by a pivot 52. The catch 51 is urged into the latched position shownin FIGS. 2 and 3 by means of a tension spring 54 which is secured by ananchor 55 to the plate 46. The catch 51 has a roller 57 rotatablydisposed thereon by means of a pivot 58. A weight 60 is held on the arm42 on the side thereof opposite to the safety gate 24 so as to cause thearm 42 to naturally rotate into its full clockwise position, thereby toallow the catch 51 to engage the arm 42 and latch it in the positionshown in FIGS. 2 and 3.

The arm 42, the latch 51 and the spring 54 are shown in FIG. 2 asdisposed on a mounting plate 46 which in turn is mounted to the masonrystructure 44 of the building, simply for the purpose of making it clearwhere the various parts are disposed relative to the elevator and to thebuilding floor 22. In reality, such parts will likely be disposed onframework interconnected with the guide rails in the hoistway. Thus, thearm 42 (and so forth) are disposed to the building in a fashion which iscommon for ancillary parts of an elevator.

On the opposite end of the safety gate 24 from the notch 43, there is asimilar notch 43a through which an arm 42a extends. The arm 42a isassociated with the same sort of apparatus as the arm 42, all of whichhave been designated by similar reference numerals to the apparatusdescribed hereinbefore, with an "a" postscript. The apparatus bearingthe "a" postscript is similarly disposed to the building by means ofordinary framing within the hoistway.

When the elevator car frame 29 is not near the transfer floor where thesafety gate 24 is disposed, it will be in the position shown in FIGS. 2and 3. When the elevator has approached the floor and is almost levelwith it, the cam structure 35 which is fastened to the bottom of theelevator car frame will approach the roller 57 as seen in FIG. 3.Immediately thereafter the cam surface 36 contacts the roller 57 causingthe catch 51 to rotate clockwise as seen in FIG. 4. However, because ofthe weight 60, the arm 42 remains in its fully clockwise position sothat the gate 24 remains in its upward, operative position. However, asthe elevator continues to rise, the roller 57 will be rotated slightlymore clockwise by the cam surface 37 (as seen in FIG. 1) and the roller38 will engage the arm 42 and rotate it anticlockwise into the positionshown in FIG. 1. This lowers the gate 24 against the force of the weight60. If desired, the movement of the gate 24 may be enhanced by slidingbetween self-lubricating guide strips, only a pair of such strips 62(FIG. 1) being shown herein. Such strips may be made of nylon, teflon,delrin, or the like. If desired, a microswitch 64 may be positioned tosense when the gate is down (FIG. 1), for control purposes.

When a cab 20 is rolled onto the elevator car frame 29, it may thendescend with the cab on it. As it begins to descend, the roller 38 alsodescends allowing the arm 42 to rotate clockwise into the position shownin FIG. 4 with the latch still rotated clockwise out of the way of thearm 42. Further descent causes the catch 51 to rotate fullyanticlockwise and to latch the arm 42 with the gate in the upwardposition as seen in FIG. 3.

The description thus far is of a configuration of the invention utilizedwith an elevator car that ascends up to a transfer floor at an upper endof a hoistway. A configuration of the invention utilized with anelevator car frame that descends to a transfer floor at a lower end of ahoistway is illustrated in FIG. 5. The principle of operation of theapparatus in FIG. 5 is identical to that illustrated and described withrespect to FIGS. 1-4, hereinbefore. Similar apparatus is marked with thesame reference numeral but with a "b" postscript.

The configuration of FIGS. 1-4 and of FIG. 5 are both shown with thehoistway disposed to the right of the landing, for ease of correlationof the two configurations. However, it may be typical that the gate 24might be disposed at a landing at the right hand end of the floor 22while a gate 24b would be disposed at a landing at a left hand end ofthe same floor (or vice versa). This is irrelevant to the invention. Thegates 24, 24b herein are disclosed as being formed as a single piece.However, the invention encompasses gates comprised of more than onepiece; for instance, in a particular elevator installation, the gateneed only block the motion of the cab 20 at its wheels 21, if desired.Similarly, the invention is disclosed as being slidable within a slot 23formed within the floor 22. However, the gate could instead be guidedand supported by suitable framing attached to the floor 22, a wall 44,or other structure within the hoistway; the nature of the means forguiding the gate is irrelevant to the invention. The hoistway door 27 isshown for completeness only; obviously, in any instance where passengerswill in no event be present on the floor 22, hoistway doors may beeliminated, if desired. On the other hand, if, in emergencies, or forany other purpose, passengers may at any time have access to the floor22, then hoistway doors 27 should, of course, be provided. These andother aspects of the disclosed embodiment can be altered in a widevariety of ways while still taking advantage of the safety gate of thepresent invention.

All of the aforementioned patent applications are incorporated herein byreference.

Thus, although the invention has been shown and described with respectto exemplary embodiments thereof, it should be understood by thoseskilled in the art that the foregoing and various other changes,omissions and additions may be made therein and thereto, withoutdeparting from the spirit and scope of the invention.

We claim:
 1. A safety gate for preventing a horizontally movableelevator cab at a landing from inadvertently entering an elevatorhoistway when an elevator car frame is not present at said landing toreceive said cab, comprising:a gate member vertically slidable betweenan upper position, in which a portion of it extends above the floor ofsaid landing adjacent to said hoistway, thereby to obstruct passage ofsaid cab along said floor toward said hoistway, and a lower position, inwhich said gate member does not obstruct passage of said cab along saidfloor toward said hoistway; a moveable actuator engaging said gatemember and moveable between a first position, in which it retains saidgate member in said upper position, and a second position, in which itretains said gate member in said lower position, said actuator movingsaid gate between said upper and lower positions as said actuator movesbetween said first and second positions; means for normally urging saidgate member into said upper position and said actuator into said firstposition; and means disposed on said elevator car frame for moving saidactuator into said second position as said elevator car frame approachessaid landing.
 2. A safety gate according to claim 1 wherein said gatemember extends across said landing the full width of said cab.
 3. Asafety gate according to claim 1 wherein said actuator is an arm pivotedin said hoistway and is engaged by a cam on said car frame to be movedfrom said first position into said second position.
 4. A safety gateaccording to claim 3 wherein said means for normally urging is a weightdisposed on said arm to provide downward vertical pull on a portion ofsaid arm which is on the opposite side of said pivot from a portion ofsaid arm which engages said gate member.
 5. A safety gate according toclaim 4 wherein said weight is disposed on a side of said arm on thesame side of said gate member as said hoistway; andsaid means disposedon said elevator car frame moves said actuator as it approaches saidlanding from a point in said hoistway below said landing.
 6. A safetygate according to claim 4 wherein said weight is disposed on a side ofsaid arm on the opposite side of said gate member from said hoistway;andsaid means disposed on said elevator car frame moves said actuator asit approaches said landing from a point in said hoistway above saidlanding.